1. Field of the Invention
This invention relates to the field of pest control, and, in particular, it relates to compositions and methods useful for controlling pests, especially plant pests.
2. Description of the Art
A variety of plant pests are known to inflict significaant damage to ornamental and crop plants and to periodically invade and thereby inconvenience residences and other structures and locations. Such pests typically include insects, gastropods, arachnids, worms, fungi, and plant pathogens such as viruses and bacteria. Such pests are generally controlled, if at all, with a variety of pesticides most of which are expensive, complex chemical compositions which are toxic to humans and/or the environment and which persist long after they are applied. Crop rotation is effective for controlling, although not eliminating, pests in several seasonal crops such as grasses, vegetables and grains and is much less innocuous than is the use of chemical pesticides. However, crop rotation serves only to reduce rather than eliminate pest populations and, of course, cannot be employed in perennial crops. Obviously, such methods of pest control suffer from numerous disadvantages including expense of the compositions or procedures (crop rotation) involved, threats to the environment which are presented by persistent chemical pesticides, and hazards to humans involved in the manufacture, transportation and application of such pesticides and to consumers of produce from pesticide-treated crops.
Sulfuric acid is known to be effective for controlling pests, and it kills essentially all pests upon contact. However, sulfuric acid is seldom used for such purposes due to its corrosivity and reactivity with almost every material which it contacts including human skin, clothing, and essentially all substrates to which it would be applied for pest control. Furthermore, sulfuric acid rapidly reacts by oxidation, dehydration, and/or sulfonation with protenatious matter and other matter of pest anatomy and with substrates such as wood bark, dormant grasses, etc. to which it might be applied to control pests, and it is consumed by such reactions. Jones, U.S. Pat. No. 4,116,664 and Verdegaal et al., U.S. Pat. No. 4,310,343, disclose that this chemical reactivity of sulfuric acid can be attenuated by reacting it with urea to form a variety of urea-sulfuric acid formulations which are useful as liquid fertilizers. Jones teaches that the resulting urea-sulfuric acid combinations are nontoxic, noncaustic, and noncorrosive to black iron and, accordingly, can be safely transported, handled, stored, and applied by ordinary farm workers and ordinary application equipment due to the absence of the chemical reactivity which is characteristic of sulfuric acid per se.